队列的应用.txt

队列的应用,利用VC++实现数据结构队列的应用

// exp_2_2.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "malloc.h"
#include "stdio.h"
#include "stdlib.h"

#define OK 1
#define ERROR 0
#define OVERFLOW -2

typedef int status;
typedef int QElemType;

#define MAXQSIZE 4
typedef struct
{
	QElemType *base;
	int front;
	int rear;
}SqQueue;
status InitQueue(SqQueue &Q)    //构造空队列
{
	Q.base=(QElemType*)malloc(MAXQSIZE*sizeof(QElemType));
	if(!Q.base)  exit(OVERFLOW);
	Q.front=Q.rear=0;
	return OK;
}
int QueueLength(SqQueue Q)  //求队队列中的元素个数
{
	return (Q.rear-Q.front+MAXQSIZE)%MAXQSIZE;
}

status EnQueue(SqQueue &Q,QElemType e)  //入队
{
	if((Q.rear+1)%MAXQSIZE==Q.front)
		return ERROR;
	Q.base[Q.rear]=e;
	Q.rear=(Q.rear+1)%MAXQSIZE;
	return OK;
}

status DeQueue(SqQueue &Q,QElemType &e)// 出队
{
	if(Q.front==Q.rear)
		return ERROR;
	e=Q.base[Q.front];
	Q.front=(Q.front+1)%MAXQSIZE;
	return OK;	
}

void Visit_Q(SqQueue Q)
{
	int i=Q.front;
	printf("\n\t当前队列状态：　");
	if(Q.front==Q.rear)
		printf("队列为空\n\n");
	else
	{
		printf("队首->");
		while(i!=Q.rear)
		{
			printf("%3d",Q.base[i]);
			i=(i+1)%MAXQSIZE;
		}
		printf("\t<-队尾\n\n");
	}
}
void  main(int argc, char* argv[])
{
	SqQueue QQ;
	InitQueue(QQ);
	QElemType e;
	int c;
	Visit_Q(QQ);
	printf("入队选１，出队选２，结束选３\n");
	scanf("%d",&c);
	while(1)
	{
		if(c==1)
		{
			printf("请输入入队元素的值(十进制整数)\n");
			scanf("%d",&e);
			if(EnQueue(QQ,e))
				printf("元素%d入队，当队列中已有%d个元素\n",e,QueueLength(QQ));
			else
				printf("!!!队列已满，%d入队失败，请先执行出队\n",e);
		}
		else
			if(c==2)
			{
				if(DeQueue(QQ,e))
					printf("元素%d出队，当前队列中还有%d个元素\n",e,QueueLength(QQ));
				else
					printf("!!!队列已空，无法执行出队操作，请先执行入队\n");
			}
			else
				if(c==3)
					break;
				else
					printf("重新选择\n");
		Visit_Q(QQ);
		printf("入队选1,出选2,结束3\n");
		scanf("%d",&c);
	}
}